I'd argue the opposite.
In my opinion the evolution of Garrosh as a character only solidifies his choice as the RIGHT chieftain in my opinion. The level of conflict between the Horde and Alliance is very enticing for people wanting to just enjoy the game, and not this fabricated political universe.
I don't want the Horde and the Alliance to be at peace, I want them to unleash upon each other the full fury of hell.
Bring the heat.
Edit: But maybe that's just because I'm an old school Warcraft player.